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long-term increases in pathogen seroprevalence in polar bears (ursus maritimus) influenced by climate change.the influence of climate change on wildlife disease dynamics is a burgeoning conservation and human health issue, but few long-term studies empirically link climate to pathogen prevalence. polar bears (ursus maritimus) are vulnerable to the negative impacts of sea ice loss as a result of accelerated arctic warming. while studies have associated changes in polar bear body condition, reproductive output, survival, and abundance to reductions in sea ice, no long-term studies have documented the imp ...202134292654
correlates of seasonal change in the body condition of an arctic top predator.climate-driven sea ice loss has led to changes in the timing of key biological events in the arctic, however, the consequences and rate of these changes remain largely unknown. polar bears (ursus maritimus) undergo seasonal changes in energy stores in relation to foraging opportunities and habitat conditions. declining sea ice has been linked to reduced body condition in some subpopulations, however, the specific timing and duration of the feeding period when bears acquire most of their energy s ...202031465583
interrelated ecological impacts of climate change on an apex predator.climate change has broad ecological implications for species that rely on sensitive habitats. for some top predators, loss of habitat is expected to lead to cascading behavioral, nutritional, and reproductive changes that ultimately accelerate population declines. in the case of the polar bear (ursus maritimus), declining arctic sea ice reduces access to prey and lengthens seasonal fasting periods. we used a novel combination of physical capture, biopsy darting, and visual aerial observation dat ...202031925853
psychological care augmented by telemedicine after a polar bear encounter at an arctic research station: a case report.background: psychologically stressful events can be particularly challenging in the wilderness or extreme environments due to a lack of immediate medical or psychological support. telemedicine consultations may provide a means to supply medical providers in austere environments with expertise when confronted with these situations. methods: in this study, we detail a case of psychological care imparted to residents at a remote, arctic research station after they encountered a polar bear. the heal ...202030912705
analyses of key genes involved in arctic adaptation in polar bears suggest selection on both standing variation and de novo mutations played an important role.polar bears are uniquely adapted to an arctic existence. since their relatively recent divergence from their closest living relative, brown bears, less than 500,000 years ago, the species has evolved an array of novel traits suited to its arctic lifestyle. previous studies sought to uncover the genomic underpinnings of these unique characteristics, and disclosed the genes showing the strongest signal of positive selection in the polar bear lineage. here, we survey a comprehensive dataset of 109 ...202032758141
interspecies comparison of the residue levels and profiles of persistent organic pollutants in terrestrial top predators.serum samples from three species of living terrestrial top predators were analysed for six groups of persistent organic pollutants (pops), such as polychlorinated biphenyls (pcbs), dichlorodiphenyltrichloroethane and its metabolites (ddts), chlordane compounds (chls), hexachlorocyclohexane isomers (hchs), hexachlorobenzene (hcb) and polybrominated diphenyl ethers (pbdes). the study included three carnivore species: lion (panthera leo), hyena (hyena brunnea) and cheetah (acinonyx jubatus). all sa ...202032006764
molecular characteristics and association analysis with litter size trait for porcine klk7 gene.kallikrein-related peptidase 7(klk7) is a tumor-related gene. in this study, the full-length coding sequence of porcine klk7 gene was cloned through rt-pcr. sequence analysis revealed that the pig klk7 gene encodes a protein of 257 amino acids which has high homology with the klk7 protein of six species: polar bear (95%), weddell seal(94%), dog (92%), pacific walrus (95%), domestic cat (92%), and amur tiger (91%). this gene is structured in five exons and four introns as revealed by computer-ass ...202031006337
comparing sea ice habitat fragmentation metrics using integrated step selection analysis.habitat fragmentation occurs when continuous habitat gets broken up as a result of ecosystem change. while commonly studied in terrestrial ecosystems, arctic sea ice ecosystems also experience fragmentation, but are rarely studied in this context. most fragmentation analyses are conducted using patch-based metrics, which are potentially less suitable for sea ice that has gradual changes between sea ice cover, than distinct "long-term" patches. using an integrated step selection analysis, we comp ...202032551061
per- and polyfluoroalkyl substances (pfas) neurotoxicity in sentinel and non-traditional laboratory model systems: potential utility in predicting adverse outcomes in human health.per- and polyfluoroalkyl substances (pfas) are a class of chemicals that were widely used in manufacturing and are now present in the environment throughout the world. it is known that various pfas are quantifiable in human in blood, but potential adverse health outcomes remain unclear. sentinel and non-traditional model species are useful to study potential toxicity of pfas in order to understand the relationship between environmental and human health. here, we present a critical review of stud ...202032549216
polish version of the white bear suppression inventory (wbsi) by wegner and zanakos: factor analysis and reliability.the main aim of this study was to adapt a polish version of the white bear suppression inventory (wbsi), originally created by wegner and zanakos (1994) to measure chronic suppression.202032447361
drivers and consequences of apex predator diet composition in the canadian beaufort sea.polar bears (ursus maritimus) rely on annual sea ice as their primary habitat for hunting marine mammal prey. given their long lifespan, wide geographic distribution, and position at the top of the arctic marine food web, the diet composition of polar bears can provide insights into temporal and spatial ecosystem dynamics related to climate-mediated sea ice loss. polar bears with the greatest ecological constraints on diet composition may be most vulnerable to climate-related changes in ice cond ...202032897468
perfluoroalkyl substances (pfass) in white whales (delphinapterus leucas) from svalbard - a comparison of concentrations in plasma sampled 15 years apart.the objective of the present study was to investigate recent concentrations of perfluoroalkyl substances (pfass) in white whales (delphinapterus leucas) from svalbard and compare them to concentrations found in white whales sampled from that same area 15 years ago. plasma collected from live-captured white whales from two time periods (2013-2014, n = 9, and 1996-2001, n = 11) were analysed for 19 different pfass. the 11 pfass detected included seven c8-c14 perfluoroalkyl carboxylates (pfcas) and ...202032302893
environmental pollutants modulate transcriptional activity of nuclear receptors of whales in vitro.this study reports the transcriptional activity of fin (balaenoptera physalus) and blue whale (balaenoptera musculus) peroxisome proliferator-activated receptor γ (pparg), glucocorticoid receptor (gr), and thyroid hormone receptor β (thrb), when exposed to 14 persistent organic pollutants (so-called "legacy" persistent organic pollutants (pops)) and a synthetic mixture of pops, using gal4-uas-based in vitro luciferase reporter gene assays. polychlorinated biphenyls (pcbs) had both agonistic and ...202032212695
impacts of oil spills on arctic marine ecosystems: a quantitative and probabilistic risk assessment perspective.oil spills resulting from maritime accidents pose a poorly understood risk to the arctic environment. we propose a novel probabilistic method to quantitatively assess these risks. our method accounts for spatiotemporally varying population distributions, the spreading of oil, and seasonally varying species-specific exposure potential and sensitivity to oil. it quantifies risk with explicit uncertainty estimates, enables one to compare risks over large geographic areas, and produces information o ...202031971780
the unique contribution of a local response group in the field investigation and management of a trichinellosis outbreak in nunavik (québec, canada).consumption of raw game meats is important for inuit health and well-being but may sometimes increase risk of exposure to parasites. in nunavik, following trichinellosis outbreaks in the 1980s caused by raw walrus consumption, a diagnostic test was developed for the region and offered to all inuit communities by 1997. despite this prevention program, an important trichinellosis outbreak occurred in 2013, affecting 18 inhabitants of inukjuak.202031637676
pictures of polar bears: using visitor employed photography to identify experience indicators in the arctic national wildlife refuge.the purpose of this research is to apply visitor employed photography (vep) to recreation management to develop indicators of the wildlife viewing experience. vep and semi-structured interviews were used at a popular polar bear viewing destination in the arctic national wildlife refuge (arctic refuge). visitors to the arctic refuge who participated in an on-site semi-structured interview were asked to participate in a vep procedure after their visit. a sample of 24 semi-structured interviews, an ...202032560998
fatty acid-based diet estimates suggest ringed seal remain the main prey of southern beaufort sea polar bears despite recent use of onshore food resources.polar bears (ursus maritimus) from the southern beaufort sea (sb) subpopulation have traditionally fed predominantly upon ice-seals; however, as the proportion of the subpopulation using onshore habitat has recently increased, foraging on land-based resources, including remains of subsistence-harvested bowhead whales (balaena mysticetus) and colonial nesting seabirds has been observed. adipose tissue samples were collected from this subpopulation during the springs of 2013-2016 and analyzed for ...202032128141
comparative review of the distribution and burden of contaminants in the body of polar bears.historical (or legacy) contaminants, such as metals and persistent organic pollutants (pops; e.g., polychlorinated biphenyls) have been measured in circumpolar subpopulations of polar bears, especially from hudson bay, east greenland, and svalbard, but substantially less is currently known about new and/or emerging contaminants such as polychlorinated naphthalenes, current-use pesticides, organotins, and polycyclic aromatic compounds (pacs). the polar bear (ursus maritimus) is an apex arctic pre ...202032556983
contrasting temporal patterns of mercury, niche dynamics, and body fat indices of polar bears and ringed seals in a melting icescape.polar bears (ursus maritimus) and ringed seals (pusa hispida) have a strong predator-prey relationship and are facing climate-associated arctic habitat loss and harmful dietary exposure to total mercury (thg) and other pollutants. however, little is known about whether both species inhabiting the same area exhibit similar temporal patterns in hg concentration, niche dynamics, and body fat indices. we used thg, δ13c, and δ15n values of western hudson bay polar bear hair (2004-2016) and ringed sea ...202032046488
adipose tissue transcriptome is related to pollutant exposure in polar bear mother-cub pairs from svalbard, norway.being at the food chain apex, polar bears (ursus maritimus) are highly contaminated with persistent organic pollutants (pops). females transfer pops to their offspring through gestation and lactation; therefore, young cubs present higher pops concentrations than their mothers. recent studies suggest that pops affect the lipid metabolism in female polar bears; however, the mechanisms and impact on their offspring remain unknown. here, we hypothesized that exposure to pops differentially alters ge ...202032808525
the impact of in-person and video-recorded animal experiences on zoo visitors' cognition, affect, empathic concern, and conservation intent.currently there are mixed results regarding the ability for media or more specifically video to increase a person's interest in conservation. however, there is a growing amount of evidence that in-person experiences at a zoo or aquarium can increase a person's interest in conservation. the goal of the current study was to examine the difference between an in-person experience viewing a polar bear training session and watching a video of the same experience on cognition, emotion, empathic concern ...202032789987
transient benefits of climate change for a high-arctic polar bear (ursus maritimus) subpopulation.kane basin (kb) is one of the world's most northerly polar bear (ursus maritimus) subpopulations, where bears have historically inhabited a mix of thick multiyear and annual sea ice year-round. currently, kb is transitioning to a seasonally ice-free region because of climate change. this ecological shift has been hypothesized to benefit polar bears in the near-term due to thinner ice with increased biological production, although this has not been demonstrated empirically. we assess sea-ice chan ...202032964662
'will polar bears melt?' a qualitative analysis of children's questions about climate change.climate change poses a grave threat to future generations, yet relatively little research examines children's understandings of the issue. this study examines the questions children ask about climate change - rather than their answers to adults' questions - exploring whether their questions suggest they view climate change as psychologically proximal or distant. children aged 10-12 from 14 uk schools took part in an online event, asking scientists questions in a 'climate zone'. the questions wer ...202032883158
climate-associated drivers of plasma cytokines and contaminant concentrations in beaufort sea polar bears (ursus maritimus).assessing polar bear (ursus maritimus) immune function in relation to environmental stressors, including habitat change, nutritional stress, pathogen prevalence, and pollution, has been identified as critical for improved understanding of the species' health. the objectives of this study were two-fold: 1) to assess the role of climate-associated factors (habitat use, body condition) in explaining the plasma concentrations of contaminants in southern beaufort sea (sb) polar bears, and 2) to inves ...202032738684
congenital grouped albinotic spots: new insights on the pathophysiology based on multimodal retinal imaging.the terms "congenital grouped albinotic spots" (cgas) and "polar bear tracks" refer to a rare, benign retinal disorder of unknown etiology characterized by multiple, predominantly unilateral, variably sized, well-circumscribed, flat white retinal spots organized in groups. to date, very few cases of cgas have been reported. the authors describe a case of cgas thoroughly characterized by multimodal imaging over an 8-year follow-up, aiming to provide new insights on the pathophysiology of this ent ...202032348540
diving deep: understanding the genetic components of hypoxia tolerance in marine mammals.marine mammals have highly specialized physiology, exhibited in many species by extreme breath-holding capabilities that allow deep dives and extended submergence. cardiovascular control and cell-level hypoxia tolerance are key features of this phenotype. identifying genomic signatures tied to physiology will be valuable in understanding these natural model species, which may generate translational opportunities to human diseases arising from hypoxic stress or tissue injury. genomic analyses hav ...202032324472
canadian polar bear population structure using genome-wide markers.predicting the consequences of environmental changes, including human-mediated climate change on species, requires that we quantify range-wide patterns of genetic diversity and identify the ecological, environmental, and historical factors that have contributed to it. here, we generate baseline data on polar bear population structure across most canadian subpopulations (n = 358) using 13,488 genome-wide single nucleotide polymorphisms (snps) identified with double-digest restriction site-associa ...202032313629
fluorine mass balance and suspect screening in marine mammals from the northern hemisphere.there is increasing evidence that the ∼20 routinely monitored perfluoroalkyl and polyfluoroalkyl substances (pfass) account for only a fraction of extractable organofluorine (eof) occurring in the environment. to assess whether pfas exposure is being underestimated in marine mammals from the northern hemisphere, we performed a fluorine mass balance on liver tissues from 11 different species using a combination of targeted pfas analysis, eof and total fluorine determination, and suspect screening ...202032160740
efficacy of aerial forward-looking infrared surveys for detecting polar bear maternal dens.denned polar bears (ursus maritimus) are invisible under the snow, therefore winter-time petroleum exploration and development activities in northern alaska have potential to disturb maternal polar bears and their cubs. previous research determined forward looking infrared (flir) imagery could detect many polar bear maternal dens under the snow, but also identified limitations of flir imagery. we evaluated the efficacy of flir-surveys conducted by oil-field operators from 2004-2016. aerial flir ...202032106278
two decades of mercury concentrations in barents sea polar bears (ursus maritimus) in relation to dietary carbon, sulfur, and nitrogen.temporal trends of total mercury (thg) were examined in female polar bear (ursus maritimus) hair (n = 199) from the barents sea in 1995-2016. in addition, hair values of stable isotopes (n = 190-197) of carbon (δ13c), sulfur (δ34s), and nitrogen (δ15n) and information on breeding status, body condition, and age were obtained. stable isotope values of carbon and sulfur reflect dietary source (e.g., marine vs terrestrial) and the nitrogen trophic level. values for δ13c and δ34s declined by -1.62 a ...202032410455
bioinspired "skin" with cooperative thermo-optical effect for daytime radiative cooling.energy-saving cooling materials with strong operability are desirable for sustainable thermal management. inspired by the cooperative thermo-optical effect in the fur of a polar bear, we develop a flexible, superhydrophobic, and reusable cooling "skin" by laminating a poly(dimethylsiloxane) film with a highly scattering polyethylene aerogel. owing to its high porosity (97.9%) and tailored pore size of 3.8 ± 1.4 μm, it can achieve superior solar reflectance (r̅sun ∼ 0.96) and high transparency to ...202032378874
full genome sequence analysis of a novel adenovirus from a captive polar bear (ursus maritimus).the presence of a novel adenovirus (adv) was detected by pcr and sequencing, in the internal organs of a captive polar bear that had died in the budapest zoo. the virus content of the samples proved to be high enough to allow for conventional sanger sequencing on pcr-amplified genomic fragments. with this approach, the sequence of the entire genome of the putative polar bear adenovirus 1 (pbadv-1) was obtained. although the genome was found to be short, consisting of 27,952 base pairs merely, wi ...202031870796
the seasonal energetic landscape of an apex marine carnivore, the polar bear.divergent movement strategies have enabled wildlife populations to adapt to environmental change. in recent decades, the southern beaufort sea subpopulation of polar bears (ursus maritimus) has developed a divergent movement strategy in response to diminishing sea ice where the majority of the subpopulation (73-85%) stays on the sea ice in summer and the remaining bears move to land. although declines in sea ice are generally considered a challenge to energy balance in polar bears residing in so ...202031850515
the stress of arctic warming on polar bears.arctic ecosystems are changing rapidly in response to climate warming. while arctic mammals are highly evolved to these extreme environments, particularly with respect to their stress axis, some species may have limited capacity to adapt to this change. we examined changes in key components of the stress axis (cortisol and its carrier protein-corticosteroid binding globulin [cbg]) in polar bears (ursus maritimus) from western hudson bay (n = 300) over a 33 year period (1983-2015) during which ti ...202032364624
identifying reliable indicators of fitness in polar bears.animal structural body size and condition are often measured to evaluate individual health, identify responses to environmental change and food availability, and relate food availability to effects on reproduction and survival. a variety of condition metrics have been developed but relationships between these metrics and vital rates are rarely validated. identifying an optimal approach to estimate the body condition of polar bears is needed to improve monitoring of their response to decline in s ...202032813753
assessment of risks of dioxins for aryl hydrocarbon receptor-mediated effects in polar bear (ursus maritimus) by in vitro and in silico approaches.polar bear (ursus maritimus) populations accumulate dioxins and related compounds (drcs) at levels that are of health concern. the toxicities of drcs are primarily mediated via aryl hydrocarbon receptor (ahr) signaling pathway. to evaluate the sensitivity and responses to drcs in polar bears, we assessed the activation potencies of polar bear-specific ahr (pbahr) by drcs through in vitro and in silico approaches. in vitro assays showed that the pbahr was as sensitive to drcs as c3h/lpr mouse ahr ...202031841312
pelagic vs coastal-key drivers of pollutant levels in barents sea polar bears with contrasted space-use strategies.in the barents sea, pelagic and coastal polar bears are facing various ecological challenges that may explain the difference in their pollutant levels. we measured polychlorinated biphenyls, organochlorine pesticides, polybrominated diphenyl ethers in fat, and perfluoroalkyl substances in plasma in pelagic and coastal adult female polar bears with similar body condition. we studied polar bear feeding habits with bulk stable isotope ratios of carbon and nitrogen. nitrogen isotopes of amino acids ...202031823610
multimodal imaging characteristics of congenital grouped hyper- and hypo-pigmented fundus lesions.the imaging characteristics of congenital grouped pigmentation of the retinal pigment epithelium (cgp-rpe) and its non-pigmented variant - grouped congenital albinotic retinal pigment epithelial spots (gcarpes) are poorly defined in the literature. our case series reports their multimodal imaging characteristics across a spectrum of presentations.202031769080
correction to: age-related differences in the attentional white bear.this article was originally published with errors in the graphs. it has been republished with corrections.202031676978
a real-time pcr assay to accurately quantify polar bear dna in fecal extracts.dna extracted from fecal samples contains dna from the focal species, food, bacteria and pathogens. most dna quantification methods measure total dna and cannot differentiate among sources. despite the desirability of noninvasive fecal sampling for studying wildlife populations, low amounts of focal species dna make it difficult to use for next-generation sequencing (ngs), where accurate dna quantification is critical for normalization. two factors are required prior to using fecal samples in ng ...202032292653
faecal glucocorticoid metabolites as a measure of adrenocortical activity in polar bears (ursus maritimus).analysis of faecal glucocorticoid metabolites (fgms) is frequently applied to assess adrenocortical activity in animal conservation and welfare studies. faecal sample collection is non-invasive and feasible under field conditions. fgm levels are also less prone to circadian rhythms, episodic fluctuations and short acute stressors than glucocorticoid (gc) levels obtained from other matrices, for example blood or saliva. to investigate the suitability of fgm measurement in polar bears (ursus marit ...202032274062
laminated fibrous membrane inspired by polar bear pelt for outdoor personal radiation management.outdoor cold stress often causes an undesired threat to public health, but devising an efficient strategy to achieve localized outdoor warming of the human body is still a great challenge. polar bear pelt can absorb sunlight and reflect thermal radiation generated inside the body, which helps in adapting to the cold environment. inspired by the radiation control strategy of the polar bear pelt, this study reports a porous ag/cellulose/carbon nanotube (cnt)-laminated nanofiber membrane, in which ...202032067458
identifying individual polar bears at safe distances: a test with captive animals.the need to recognise individuals in population and behavioural studies has stimulated the development of various identification methods. a commonly used method is to employ natural markers to distinguish individuals. in particular, the automated processing of photographs of study animals has gained interest due to the speed of processing and the ability to handle a high volume of records. however, automated processing requires high-quality photographs, which means that they need to be taken fro ...202032053691
the clock keeps ticking: circadian rhythms of free-ranging polar bears.life in the arctic presents organisms with multiple challenges, including extreme photic conditions, cold temperatures, and annual loss and daily movement of sea ice. polar bears (ursus maritimus) evolved under these unique conditions, where they rely on ice to hunt their main prey, seals. however, very little is known about the dynamics of their daily and seasonal activity patterns. for many organisms, activity is synchronized (entrained) to the earth's day/night cycle, in part via an endogenou ...202031975640
multimodal semantic revision during inferential processing: the role of inhibitory control in text and picture comprehension.although language comprehension usually requires multimodal information, no study to date has investigated how comprehenders deal with the revision of a text's interpretation when different modalities are involved. twenty-four young adults listened to a story prompting an inference (e.g., polar bear), and then saw a picture that was either consistent (polar bear) or inconsistent but still plausible (penguin). larger negativity (n400) in the inconsistent picture indicated successful inferential m ...202031904356
a critical review about neurotoxic effects in marine mammals of mercury and other trace elements.marine mammals are more exposed to mercury (hg) than any others animals in the world. as many trace elements, hg it is able to impair the brain function, which could be a cause of population decline. nevertheless, these issues have been scarcely studied because of the technical and ethical difficulties. we conducted a systematic review about marine mammals' brain exposition to hg and other trace elements, and their neurotoxic effects. information was scarce and the lack of standardization of nom ...202031896013
accounting for phenology in the analysis of animal movement.the analysis of animal tracking data provides important scientific understanding and discovery in ecology. observations of animal trajectories using telemetry devices provide researchers with information about the way animals interact with their environment and each other. for many species, specific geographical features in the landscape can have a strong effect on behavior. such features may correspond to a single point (eg, dens or kill sites), or to higher dimensional subspaces (eg, rivers or ...201930859552
depletion of hemoglobin transcripts and long-read sequencing improves the transcriptome annotation of the polar bear (ursus maritimus).transcriptome studies evaluating whole blood and tissues are often confounded by overrepresentation of highly abundant transcripts. these abundant transcripts are problematic, as they compete with and prevent the detection of rare rna transcripts, obscuring their biological importance. this issue is more pronounced when using long-read sequencing technologies for isoform-level transcriptome analysis, as they have relatively lower throughput compared to short-read sequencers. as a result, long-re ...201931379921
global change-driven use of onshore habitat impacts polar bear faecal microbiota.the gut microbiota plays a critical role in host health, yet remains poorly studied in wild species. polar bears (ursus maritimus), key indicators of arctic ecosystem health and environmental change, are currently affected by rapid shifts in habitat that may alter gut homeostasis. declining sea ice has led to a divide in the southern beaufort sea polar bear subpopulation such that an increasing proportion of individuals now inhabit onshore coastal regions during the open-water period ('onshore b ...201931378786
age-related differences in the attentional white bear.the cognitive aging literature suggests that aging populations exhibit impairments in the proactive inhibition of attention. although proactive inhibition is often preceded by the allocation of attention toward the predicted or known spatial location of to-be-ignored stimuli, proactive allocation of attention has not been assessed in aging populations. in this study, an older and younger cohort engaged in the attentional-white-bear paradigm which measures proactive allocation of attention. in th ...201931183745
intrinsic rivalry. can white bears help us with the other side of consciousness?studies of consciousness have traditionally been based mainly upon the perceptual domains of consciousness. however, there is another side of consciousness, represented by various types of intrinsic conscious experiences. even though intrinsic experiences can represent up to 50% of our conscious experiences, they are still largely neglected in conscious studies. we assume there are two reasons for this. first, the field of intrinsic conscious experiences is methodologically far more problematic ...201931133953
modeling optimal responses and fitness consequences in a changing arctic.animals must balance a series of costs and benefits while trying to maximize their fitness. for example, an individual may need to choose how much energy to allocate to reproduction versus growth, or how much time to spend on vigilance versus foraging. their decisions depend on complex interactions between environmental conditions, behavioral plasticity, reproductive biology, and energetic demands. as animals respond to novel environmental conditions caused by climate change, the optimal decisio ...201931077520
environmental contaminants modulate the transcriptional activity of polar bear (ursus maritimus) and human peroxisome proliferator-activated receptor alpha (ppara).peroxisome proliferator-activated receptor alfa (ppara/nr1c1) is a ligand activated nuclear receptor that is a key regulator of lipid metabolism in tissues with high fatty acid catabolism such as the liver. here, we cloned ppara from polar bear liver tissue and studied in vitro transactivation of polar bear and human ppara by environmental contaminants using a luciferase reporter assay. six hinge and ligand-binding domain amino acids have been substituted in polar bear ppara compared to human pp ...201931061404
how many cubs can a mum nurse? maternal age and size influence litter size in polar bears.life-history theory predicts that females' age and size affect the level of maternal investment in current reproduction, balanced against the future reproductive effort, maintenance and survival. using long-term (30 years) individual data on 193 female polar bears ( ursus maritimus), we assessed age- and size-specific variation on litter size. litter size varied with maternal age, younger females had higher chances of losing a cub during their first months of life. results suggest an improvement ...201931039729
plasmon-activated water can prolong existing sea-ice habitats to potentially save polar bears.due to increasing global warming resulting from the greenhouse effect, subsequent environmental impacts and corresponding ecological influences are unavoidable. these problems are becoming more serious with time. due to rising temperatures, the survival crisis of polar bears is a very often reported issue, because polar bears are encountering shortened seasons for catching prey on their sea-ice habitat. in this work, we report an innovative and facile strategy to save polar bears via prolonging ...201931320695
geographical assignment of polar bears using multi-element isoscapes.wide-ranging apex predators are among the most challenging of all fauna to conserve and manage. this is especially true of the polar bear (ursus maritimus), an iconic predator that is hunted in canada and threatened by global climate change. we used combinations of stable isotopes (13c,15n,2h,18o) in polar bear hair from > 1000 individuals, sampled from across much of the canadian arctic and sub-arctic, to test the ability of stable isotopic profiles to 'assign' bears to (1) predefined managed s ...201931253845
distract yourself: prediction of salient distractors by own actions and external cues.distracting sensory events can capture attention, interfering with the performance of the task at hand. we asked: is our attention captured by such events if we cause them ourselves? to examine this, we employed a visual search task with an additional salient singleton distractor, where the distractor was predictable either by the participant's own (motor) action or by an endogenous cue; accordingly, the task was designed to isolate the influence of motor and non-motor predictive processes. we f ...201930588545
estimating the energy expenditure of free-ranging polar bears using tri-axial accelerometers: a validation with doubly labeled water.measures of energy expenditure can be used to inform animal conservation and management, but methods for measuring the energy expenditure of free-ranging animals have a variety of limitations. advancements in biologging technologies have enabled the use of dynamic body acceleration derived from accelerometers as a proxy for energy expenditure. although dynamic body acceleration has been shown to strongly correlate with oxygen consumption in captive animals, it has been validated in only a few st ...201931015999
thermal insulation design bioinspired by microstructure study of penguin feather and polar bear hair.nature is an amazing source of inspiration for the design of thermal insulation strategies, which are key for saving energy. in nature, thermal insulation structures, such as penguin feather and polar bear hair, are well developed; enabling the animals' survival in frigid waters. the detailed microscopy investigations conducted in this study, allowed us to perform microstructural analysis of these thermally insulating materials, including statistical measurements of keratin fiber and pore dimens ...201931005607
temporal trends of persistent organic pollutants in barents sea polar bears ( ursus maritimus) in relation to changes in feeding habits and body condition.temporal trends of persistent organic pollutants (pops: pcbs, oh-pcbs, p, p'-dde, hcb, β-hch, oxychlordane, bde-47, and 153) in relation to changes in feeding habits and body condition in adult female polar bears ( ursus maritimus) from the barents sea subpopulation were examined over 20 years (1997-2017). all 306 samples were collected in the spring (april). both stable isotope values of nitrogen (δ15n) and carbon (δ13c) from red blood cells declined over time, with a steeper trend for δ13c bet ...201930548071
a stochastic game model of searching predators and hiding prey.when the spatial density of both prey and predators is very low, the problem they face may be modelled as a two-person game (called a 'search game') between one member of each type. following recent models of search and pursuit, we assume the prey has a fixed number of heterogeneous 'hiding' places (for example, ice holes for a seal to breathe) and that the predator (maybe polar bear) has the time or energy to search a fixed number of these. if he searches the actual hiding location and also suc ...201930940027
age and seasonal variation in testis and baculum morphology in east greenland polar bears (ursus maritimus) in relation to high concentrations of persistent organic pollutants.persistent organic pollutants (pops) are found in high concentrations in the artic. polar bears (ursus maritimus) are one of the most exposed mammals in the arctic and are thereby vulnerable to reproductive disruption. the aim of this study was to investigate male polar bear reproduction based on a detailed evaluation of testis histology and to assess possible effects of environmental chemicals on male polar bear reproduction. reproductive groups that were identified based on histology were as f ...201930928855
potential clinical utility of erc-2 yeast phase lysate antigen for antibody detection in dogs with blastomycosis.four blastomyces antigens erc-2 (b. gilchristii, dog, wisconsin), b5929 (human, minnesota), 597 (human, wisconsin), and t-27 (polar bear, tennessee) were tested against 31 serum specimens from dogs with blastomycosis and 19 from healthy dogs. all antigens detected antibody; efficacy varied. erc-2 showed the highest elisa mean absorbance value of 3.00 followed by t-27. test performance varied by sample geographic origin. further study is needed to determine if erc-2 antigens may be clinically use ...201930544205
the use of hair as a proxy for total and methylmercury burdens in polar bear muscle tissue.polar bears (ursus maritimus) are an ecologically important species in the arctic, whose health, and that of the people whose livelihoods depend on them, are increasingly affected by climate change and the bioaccumulation of contaminants such as mercury (hg). although methylmercury (mehg) is the toxic form of hg that biomagnifies up food webs, risk assessment studies typically only report on total hg (thg) concentrations because it is cheaper to quantify. furthermore, hair is commonly analysed f ...201931412508
are polar bear habitat resource selection functions developed from 1985-1995 data still useful?greenhouse-gas-induced warming in the arctic has caused declines in sea ice extent and changed its composition, raising concerns by all circumpolar nations for polar bear conservation.negative impacts have been observed in three well-studied polar bear subpopulations. most subpopulations, however, receive little or no direct monitoring, hence, resource selection functions (rsf) may provide a useful proxy of polar bear distributions. however, the efficacy of rsfs constructed from past data, that ...201931410267
investigating the relationship between distinctive patterns of emotion regulation, trauma exposure and psychopathology among refugees resettled in australia: a latent class analysis.background: emotion regulation difficulties are common among individuals from refugee backgrounds. little is known, however, about whether there are specific patterns relating to the types of emotion regulation strategies commonly employed by refugees, nor how this relates to psychopathology. moreover, wider literature on emotion regulation has primarily focused on examining specific emotion regulation strategies in isolation, rather than patterns of emotion regulation across multiple strategies ...201931552131
reference intervals for blood-based biochemical analytes of southern beaufort sea polar bears.accurate reference intervals (ris) for commonly measured blood-based analytes are essential for health monitoring programmes. baseline values for a panel of analytes can be used to monitor physiologic and pathophysiologic processes such as organ function, electrolyte balance and protein catabolism. our reference population includes 651 serum samples from polar bears (ursus maritimus) from the southern beaufort sea (sb) subpopulation sampled in alaska, usa, between 1983 and 2016. to establish ri ...201931548889
how not to fall for the white bear: combined frequency and recency manipulations diminish negation effects on overt behavior.processing negated mental representations comes with a price: not only are negations harder to resolve than affirmative statements, but they may even invoke ironic effects, producing the exact opposite of the intended outcome. negation effects also behave ironically when subjected to high-frequency training; when they are confronted often, the difficulty to process negations strangely increases. here we show that negation effects can be mitigated under certain circumstances. based on models of c ...201931517231
the impact of emotional regulation strategies on pain catastrophizing in the context of interpersonal relationships.the communal coping model suggests that pain catastrophizing may serve to elicit support from others. what is not known is how emotional regulation, namely emotional inhibition, impacts pain catastrophizing within the context of an interpersonal relationship. individuals who have a greater tendency to emotionally inhibit may have a greater likelihood to use catastrophizing as a means for seeking support, particularly in relationships characterized by satisfaction and emotional validation.201931513053
aviation, melting sea-ice and polar bears.on 11 may 2019, the mauna loa, hawaii, earth system research laboratory reported the highest co2 concentration in human meteorological history. continuing co2 rise will devastate ecosystems, and ice dependent species like polar bears ultimately will disappear. commercial aviation is presently a relatively small co2 contributor, but this co2 intensive mode of transportation is projected to increase greatly. scientists and conservationists are often among the most frequent of flyers, despite their ...201931671313
babesia sp. infection in a zoo-housed polar bear (ursus maritimus).a 28-year-old female polar bear (ursus maritimus) housed in a zoo in upstate new york presented with acute inappetence and lethargy. the bear's condition rapidly deteriorated, and because laboratory testing indicated severe hepatic and renal disease, the bear was humanely euthanized. examination of a blood smear from a sample collected just prior to euthanasia revealed the presence of intra-erythrocytic inclusions, which were identified as babesia sp. by pcr. although it is unclear if babesiosis ...201931796190
survey of arctic alaskan wildlife for influenza a antibodies: limited evidence for exposure of mammals.influenza a viruses (iavs) are maintained in wild waterbirds and have the potential to infect a broad range of species, including wild mammals. the arctic coastal plain of alaska supports a diverse suite of species, including waterfowl that are common hosts of iavs. mammals co-occur with geese and other migratory waterbirds during the summer breeding season, providing a plausible mechanism for interclass transmission of iavs. to estimate iav seroprevalence and identify the subtypes to which gees ...201930289331
bioaccumulation and biomagnification of perfluoroalkyl acids and precursors in east greenland polar bears and their ringed seal prey.the bioaccumulation and biomagnification of 22 major perfluoroalkyl substances (pfas) were investigated in tissues of polar bears (ursus maritimus) and their major prey species, the ringed seal (pusa hispida), from the scoresby sound region of east greenland. in polar bear liver the mean σ4pfsa (perfluoroalkyl sulfonic acid) concentration (c4, c6, c8 and c10) was 2611 ± 202 ng/g wet weight (ww; 99% perfluorooctane sulfonate (pfos)) and two orders of magnitude higher than the 20 ± 3 ng/g ww (89% ...201931252131
evidence of intraspecific prey switching: stage-structured predation of polar bears on ringed seals.prey switching is a phenomenon in which a predator disproportionately consumes the most abundant prey type, and switches to preferentially consume another prey type if the first becomes relatively rare. this concept may be expanded outside of its usual usage describing switching between prey species (interspecific), to describe switching between prey stages within a given species (intraspecific). polar bears (ursus maritimus) are thought to seek out naive ringed seal (pusa hispida) pups in the s ...201930456487
fatal hepatic sarcocystosis in a free-ranging grizzly bear cub associated with sarcocystis canis-like infection.we describe herein fatal hepatic sarcocystosis in a free-ranging grizzly bear ( ursus arctos horribilis) cub with apicomplexan infection of the liver and brain, both demonstrating 100% homology for sarcocystis canis and s. arctosi. fatal hepatic sarcocystosis in dogs has been etiologically associated with intrahepatic schizonts of s. canis. in black and polar bears, a s. canis-like organism produces schizonts in the liver and massive hepatic necrosis. although intramuscular sarcocysts, taxa s. a ...201930698508
synteny search identifies carnivore y chromosome for evolution of male specific genes.the explosive accumulation of mammalian genomes has provided a valuable resource to characterize the evolution of the y chromosome. unexpectedly, the y-chromosome sequence has been characterized in only a small handful of species, with the majority being model organisms. thus, identification of y-linked scaffolds from unordered genome sequences is becoming more important. here, we used a syntenic-based approach to generate the scaffolds of the male-specific region of the y chromosome (msy) from ...201930019860
do trait emotional intelligence and dispositional mindfulness have a complementary effect on the children's and adolescents' emotional states?mindfulness is both a non-judgmental and present-centered awareness, which has been applied to reduce negative emotions. on the other hand, trait emotional intelligence (tei) is the way of how good people perceive their emotional intelligence abilities (perceiving, expressing, understanding, and regulating emotions), which are involved in people's social functioning. this empirical study was designed to analyze whether dispositional mindfulness (dm) and tei have a potential combined role for chi ...201931920855
ironic and overcompensating processes under avoidance instructions in motor tasks: an attention imbalance model with golf-putting evidence.thought-suppression research showed, when asked to suppress a given thought (e.g., a white bear), people ironically report thinking more of the suppressed thought. testing motor performance given avoidance goals (e.g., avoid putting the ball short of the target in golf) represents an interest to transfer thought-suppression findings to motor tasks. however, instead of revealing an ironic process, motor studies showed mixed results, suggesting a coexistence of ironic and overcompensating processe ...201931464468
the relevance of mindfulness and thought suppression to scrupulosity.the purpose of this study was to examine the relevance of the mindfulness and thought suppression to scrupulosity, or religious obsessions. it was hypothesized that scrupulosity would be negatively associated trait mindfulness and positively associated with thought suppression. it was also hypothesized that thought suppression and mindfulness would mediate the association between scrupulosity and symptoms of obsessive-compulsive disorder (ocd). a survey-based study was conducted to test these hy ...201932746386
from polar bears to cell polarity and everything in between: 2018 in review. 201930808619
unpacking cognitive emotion regulation in eating disorder psychopathology: the differential relationships between rumination, thought suppression, and eating disorder symptoms among men and women.while previous literature suggests that emotion dysregulation is a salient factor contributing to the onset and maintenance of eating disorders (eds), less is known about how maladaptive, cognitively oriented regulation strategies such as rumination and thought suppression may be uniquely related to ed symptoms in men and women. the present study sought to examine the independent associations of ruminative brooding and thought suppression with ed symptoms, after controlling for negative affect i ...201930677597
state of knowledge on current exposure, fate and potential health effects of contaminants in polar bears from the circumpolar arctic.the polar bear (ursus maritimus) is among the arctic species exposed to the highest concentrations of long-range transported bioaccumulative contaminants, such as halogenated organic compounds and mercury. contaminant exposure is considered to be one of the largest threats to polar bears after the loss of their arctic sea ice habitat due to climate change. the aim of this review is to provide a comprehensive summary of current exposure, fate, and potential health effects of contaminants in polar ...201930901781
heightened immune system function in polar bears using terrestrial habitats.climate change is altering the distribution of some wildlife species while warming temperatures are facilitating the northward expansion of pathogens, potentially increasing disease risk. melting of arctic sea ice is increasingly causing polar bears (ursus maritimus) of the southern beaufort sea (sbs) to spend summer on land, where they may encounter novel pathogens. here, we tested whether sbs polar bears on shore during summer exhibited greater immune system activity than bears remaining on th ...201930403916
concentrations of legacy and new contaminants are related to metabolite profiles in hudson bay polar bears.there are very few metabolomics assessments based on field accumulated, uncontrolled contaminant exposures in wildlife, particularly in the arctic. in the present study, targeted metabolomics and contaminant data were analyzed together to assess potential influences of contaminant exposure on the hepatic metabolome of male polar bears (n = 29) from the southern and western hudson bay (shb and whb respectively), canada. the 29 metabolites identified as important in the differentiation of the two ...201930384230
detection and genome characterization of two novel papillomaviruses and a novel polyomavirus in tree shrew (tupaia belangeri chinensis) in china.papillomaviruses (pvs) and polyomaviruses (pyvs) infect diverse vertebrates including human and cause a broad spectrum of outcomes from asymptomatic infection to severe disease. there has been no pv and only one pyv detected in tree shrews, though the genomic properties of tree shrews are highly similar to those of the primates.201930885224
clostridium (clostridioides) difficile shedding by polar bears (ursus maritimus) in the canadian arctic.clostridium (clostridioides) difficile has been identified in humans and a wide range of animal species, but there has been little study of remote animal populations with limited human contact. the objective of this study was to determine the prevalence and types of c. difficile in wild and captive polar bears (ursus maritimus). fecal samples were collected from two populations of wild polar bears in nunavut canada; m'clintock channel and hudson strait (davis strait or foxe basin), as well as fr ...201930880150
polar bear evolution is marked by rapid changes in gene copy number in response to dietary shift.polar bear (ursus maritimus) and brown bear (ursus arctos) are recently diverged species that inhabit vastly differing habitats. thus, analysis of the polar bear and brown bear genomes represents a unique opportunity to investigate the evolutionary mechanisms and genetic underpinnings of rapid ecological adaptation in mammals. copy number (cn) differences in genomic regions between closely related species can underlie adaptive phenotypes and this form of genetic variation has not been explored i ...201931209046
cortical mechanisms of prioritizing selection for rejection in visual search.in visual search, the more one knows about a target, the faster one can find it. surprisingly, target identification is also faster with knowledge about distractor-features. the latter is paradoxical, as it implies that to avoid the selection of an item, the item must somehow be selected to some degree. this conundrum has been termed the "ignoring paradox", and, to date, little is known about how the brain resolves it. here, in data from four experiments using neuromagnetic brain recordings in m ...201829691330
the genome of the north american brown bear or grizzly: ursus arctos ssp. horribilis.the grizzly bear (ursus arctos ssp. horribilis) represents the largest population of brown bears in north america. its genome was sequenced using a microfluidic partitioning library construction technique, and these data were supplemented with sequencing from a nanopore-based long read platform. the final assembly was 2.33 gb with a scaffold n50 of 36.7 mb, and the genome is of comparable size to that of its close relative the polar bear (2.30 gb). an analysis using 4104 highly conserved mammali ...201830513700
discrimination factors of carbon and nitrogen stable isotopes from diet to hair in captive large arctic carnivores of conservation concern.stable isotope analysis is widely used to reconstruct diet, delineate trophic interactions, and determine energy pathways. such ecological inferences are based on the idea that animals are, isotopically, what they eat but with a predictable difference between the isotopic ratio of a consumer and that of its diet, coined as the discrimination factor. providing correct estimates of diet-consumer isotopic discrimination in controlled conditions is key for a robust application of the stable isotopes ...201830030922
immunologic, reproductive, and carcinogenic risk assessment from pop exposure in east greenland polar bears (ursus maritimus) during 1983-2013.polar bears (ursus maritimus) are among the world's highest trophic level marine predators and as such have some of the highest tissue concentrations of organohalogen contaminants (ohcs) among arctic biota. in this paper we present the results of a three decade (1983-2013) risk assessment of ohc exposure and effects on reproduction, immunity, and cancer (genotoxicity) in polar bears from central east greenland. risk of adverse effects are evaluated using a risk quotient (rq) approach with deriva ...201829883763
effects of biometrics, location and persistent organic pollutants on blood clinical-chemical parameters in polar bears (ursus maritimus) from svalbard, norway.in the present study, blood clinical-chemical parameters (bccps) were analysed in 20 female and 18 male svalbard polar bears (ursus maritimus) captured in spring 2007. the aim was to study how age, body condition (bc), biometrics, plasma lipid content and geographical location may confound the relationship between persistent organic pollutants (pops) including pcbs, hcb, chlordanes, ddts, hchs, mirex and oh-pcbs and the concentrations of 12 specific bccps (hematocrit [hct], hemoglobin [hb], aspa ...201829860211
hundreds of unrecognized halogenated contaminants discovered in polar bear serum.exposure of polar bears (ursus maritimus) to persistent organic pollutants was discovered in the 1970s, but recent evidence suggests the presence of unknown toxic chemicals in their blood. protein and phospholipid depleted serum was stirred with polyethersulfone capillaries to extract a broad range of analytes, and nontarget mass spectrometry with "fragmentation flagging" was used for detection. hundreds of analytes were discovered belonging to 13 classes, including novel polychlorinated bipheny ...201830376612
polar bears turn to whale meat as their hunting grounds melt. 201830327510
tracking arctic marine mammal resilience in an era of rapid ecosystem alteration.global warming is significantly altering arctic marine ecosystems. specifically, the precipitous loss of sea ice is creating a dichotomy between ice-dependent polar bears and pinnipeds that are losing habitat and some cetaceans that are gaining habitat. while final outcomes are hard to predict for the many and varied marine mammal populations that rely on arctic habitats, we suggest a simplified framework to assess status, based upon ranking a population's size, range, behavior, and health. this ...201830300350
effects of tanning on the stable isotopic compositions of hair.we investigated the effect of tanning on the stable isotopic compositions (cnhos) of hair keratin. samples of hair from polar bear (ursus maritimus) hides were collected before and after the tanning process from a commercial tannery. with the exception of sulphur isotopes, tanning did not alter the stable isotopic compositions of hair. δ34s values were slightly more positive (1 per mil) in hair that had gone through the tanning process, likely as a result of the tanning agent, alum (al2(so4)3) o ...201830286339
development of on-shore behavior among polar bears (ursus maritimus) in the southern beaufort sea: inherited or learned?polar bears (ursus maritimus) are experiencing rapid and substantial changes to their environment due to global climate change. polar bears of the southern beaufort sea (sb) have historically spent most of the year on the sea ice. however, recent reports from alaska indicate that the proportion of the sb subpopulation observed on-shore during late summer and early fall has increased. our objective was to investigate whether this on-shore behavior has developed through genetic inheritance, asocia ...201830250663
polar bear health in environmental science and translational medicine. 201830227316
metagenomic composition analysis of an ancient sequenced polar bear jawbone from svalbard.the sequencing of ancient dna samples provides a novel way to find, characterize, and distinguish exogenous genomes of endogenous targets. after sequencing, computational composition analysis enables filtering of undesired sources in the focal organism, with the purpose of improving the quality of assemblies and subsequent data analysis. more importantly, such analysis allows extinct and extant species to be identified without requiring a specific or new sequencing run. however, the identificati ...201830200636
evidence for ussurian tube-nosed bats (murina ussuriensis) hibernating in snow.surviving winter is a challenge for endothermic animals living at high latitudes. in bats, some species migrate to milder climates in winter, but others presumably stay and hibernate in thermally buffered roosts. however, we know little about where, or in what roosts bats hibernate. ussurian tube-nosed bats (murina ussuriensis) have occasionally been observed under or near the surface of snow. we collected the details of those accounts and used our own observations to conclude that these bats hi ...201830104736
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